Interestingly, Z-VAD-FMK significantly decreased the activation of caspase-9 but not caspase-8 upon tiplaxtinin (Fig. 6N), supporting the notion that caspase-9 activation plays a critical role in tiplaxtinin-induced apoptosis in CML cells. This evidence concerns the gene CASP9 and chronic myelogenous leukemia, BCR-ABL1 positive.